Warp tensioning and letting-off device for weaving looms



June 16, 1936. AK A 2,044,218

WARP TENSIONING AND LETTING-OFF DEVICE FOR'WEAVING LOOMS Filed Jan; 3, 1935 2 Sheets-Sheet '1 1| mumm l? J L I. P;

June 16, H E D I WARP TENSIONING AND LETTING-OFF DEVICE FOR WEAVING LOOMS Filed Jan. 3, 1935 2 Sheets-Sheet 2 Patented June 16, 1936 NETE STAT WARP TENSIONING AND LETTING-OFF DEVICE FOR WEAVING LOOMS Application January 3, 1935, Serial No. 295 In Great Britain January 20, 1934 15 Claims.

The present invention relates to Weaving looms, and more particularly to warp tensioning and warp let-oil devices for looms.

It is well-known that when weaving with or- 5 dinary looms, the tension in the warp is greatest during the shedding and least during the beat-up when all the warps are substantially straight and parallel. Thus the warp is liable to be overstretched during the shedding thereby involving m permanent injury thereto and to be allowed to remain over-slack during the beat-up whereby the appearance of the finished cloth may be impaired.

The primary object of the present invention is to provide a compensating motion adapted to maintain the warp at a substantially constant tension throughout all the steps in a weaving operation.

- According to the present invention, a weaving loom has a freely angularly displaceable warp beam which is provided with loading means adapted to apply a constant turning moment thereto in one direction.

According to another aspect of the invention, a

weaving loom has a freely angularly displaceable warp beam, loading means for applying a turning moment to the warp beam in-opposition to the turning moment applied thereto by the warp and a means for automatically varying the relative angular disposition of the warp beam and said loading means to maintain substantially constant the effect of said loading means as the warp beam is rotated to let ofi the warp.

M According to a still further aspect of the invention, a weaving loom has a freely angularly displaceable warp beam, means for applying a turning moment to said warp beam from a loading means acting in a given direction to oppose A, the turning moment applied to the warp beam by the warp and -means for automatically varying the angle of connection of said loading means to the warp beam to maintain substantially constant the-lever arm of said loading means with respect to the warp beam as the warp beam isrotated to let off the warp. Mechanical means independent of said, loading means are provided to positively rotate the warp beam to let on the warp and. at the same time to alter the relative angular dis- 50 position of the warpv beam and-said loading means and the connection between the warp beam and the loading means may include a toothed gear mechanism driven from a moving part of the loom to permit change in the relative angular dispositionof the warp beam and loading means without releasing the warp beam from the loading means.

Preferably the warp beam and back carrier are adapted for common angular displacement about a common axis, the said loading means acting commonly upon the loading means and back carrier to apply a turning moment thereto. Furthermore, the rate of positive rotation of the warp beam may be governed by the angular disposition of the warp beam and back carrier. For this purpose the initial position of an actuating element adapted to effect positive rotation of the warp beam and to be periodically displaced into a predetermined terminal position by a moving part of the. loom, may be governed by the angular disposition of the warp beam and the back carrier.

Preferably the axis of angular displacement of the warp beam and back carrier is coincident with the axisof rotation of the warp beam.

The invention is more particularly described withreference to the accompanying drawings, in which:-

Figure lis a side elevation of the rear part of a loom.

Figure 2 is a corresponding rear view, whilst Figures 3 and 4 are views of details of the construction.

The warp'beam l is supported by bearings 2 so as to-be freely angularly displaceable; each bearing 2 has a pair of spaced projections 3 for engagement with a slot 4 of a support or bracket member 5 detachably connected to the loom framefi. The bracket members 5 can be vertically adjusted with relation to the loom frame 6 by virtue of the provision of elongated slots I in the loom frame. The bearings 2 can be adjusted upwardly and downwardly by means of adjusting screws 50. A pair of substantially vertically disposed brackets 8 are mounted on the journals 9 of the warp beam, the journals 9 being supported in the bearings 2 and the warp beam being supported from the journals 9 by axially projecting pins or spindles I0.

Each bracket 8 has a bearing element II at its upper end for the reception of the ends of the back carrier [2. The bearing elements II are adjustable relatively to the brackets 8 whereby the spacing of the back carrier from the warp beam can be adjusted if desired.

The back carrier I2 carries adjacent each end a rotatable toothed wheel I3 each of which meshes with a toothed rim it one of which is secured to each end of the warp beam. The toothed wheels [3 are driven through the back carrier l2 by means of a worm wheel 15 meshing with a worm l6 fixedly mounted upon a spindle I! secured in bearings l8, I9, extending forwardly from the brackets 8. At the lower end of the spindle I7 is secured a ratchet wheel 28 and beneath this a bell-crank lever 2| is freely pivoted on the spindle I! and bears a pawl 22 which is pressed into engagement with the ratchet wheel 28 by means of a spring 23. A push-rod 24 is pivotally connected to the bell-crank lever 2| through a link 25 having pivots at right-angles to one another to pro-' vide a universal joint connection between the push-rod and the bell-crank lever. The pushrod has a collar 26 adjacent one end thereof, and engages through a bearing 2! upon the slay 28 so that the collar 26 is engaged by the bearing 21 during the oscillating movement of the slay to cause displacement of the push-rod into a predetermined terminal position dependent upon the position of the collar 26 upon the push-rod and the amplitude of movement of the slay.

A collar 29 on the push-rod is adapted for engagement by an abutment member 38 formed as a rectilinearly bent rod having an eye 3| at its free end for engagement around the push-rod 24 and pivotally connected to the bracket 8 by means of a pivot bearing 32. A spring 33 engages between the eye 3| of the rod 38 and a collar. 34 so as normally to press the push-rod to the right, that is, towards the slay.

It will thus be appreciated that the initial position of the push-rod at the commencement of its displacement by abutment of the collar 26 with the bearing 21 will be dependent upon the position of the collar 29 and upon the position of the abutment member with respect to the bracket 8. The position of the abutment member 38 with respect to the bracket 8 can be adjusted by releasing a set pin 35 in the pivot bearing 32, whereby the rod 38 can be displaced to the right or the left and the pin 35 tightened up again.

It will be appreciated that if the rod 38 is displaced to the right the stroke of the push-rod 24 will be increased, whilst if the rod is displaced to the left, the stroke will be decreased.

Furthermore, it will be observed that if the brackets 8 are angularly displaced in a clockwise direction as viewed in Figure 1, the rod 38 will move to the right to increase the stroke of the push-rod 24. Thus during the operation of the loom the oscillation of the slay will impart a periodic displacement to the push-rod 24 and periodic angular displacement to the bell-crank lever 2|. The amplitude of this displacement during the operation of the loom will depend upon the angular position of the brackets 8, that is on the position of the back carrier [2 so that if for a short period the warp is being taken in more rapidly than it is let ofi, the brackets 8 and rod 3% will move to the right to cause the rate of let oif to be increased.

Conversely, if the brackets 8 and rod 38 move to the left the rate of let off will'be decreased.

If the teeth of the ratchet wheel are relatively coarse, compared with the periodic angular displacement of the bell-crank lever 2|, there will be no angular displacement whatever of the rod l1 corresponding to certain of the strokes of the push-rod 24. A hand wheel 36 is secured at the upper end of the spindle I! for efiecting manual let off of warp.

Tension is applied to the warp through the back carrier and warp beam by means of weights 3?, suspended by means of chains 38 from quadrants 39 extending rearwardly from the brackets 8. The quadrants are arranged co-axially with the axis of rotation of the warp beam and the warp beam assembly so that the lever arm of the weights 31 with respect to the warp beam and its assembly will remain constant despite angular displacement of the brackets 8.

The warp beam assembly including the brackets 8, back carrier I2, spindle l1 and associated parts, are balanced by balance weights 40 which are adjustably connected to the lower ends of the brackets 8, whereby the angular disposition of the brackets 8 will have nobearing upon the warp tension.

Abutment screws 4| are mounted in threaded lugs 42 extending from the balance weights 40, the abutment screws 4| being adapted for engagement with the frame 6 to limit angular displacement of the brackets 8, in the anti-clockwise direction. A brake consisting of a spring leaf 43 connected to the bracket 8 is provided for preventing over-run of the spindle H. The warp is indicated-by reference numeral 44, and is preferably led oil the warp beam to the back carrier in the manner indicated by the dotted line 45.

If desired, however, the warp may be led from the warp beam in the manner indicated by the chain dotted line 46, but in the latter case it will be necessary to employ worm 16 of opposite angle.

One of the chief advantages of the present invention resides in the fact that the tension of the warp is wholly independent of the let-off, the letofi being effected mechanically and independently of the weighting of the'warp beam.

Furthermore, the warp beam, in addition to its positive rotation from the gear mechanism driving the same, is freely angularly displaceable in common with the brackets 8 and back carrier l2 under the influence of the loading weights 31 and the warp tension acting in opposite directions. Thus the warp tension is dependent upon the loading weights 3! and is unaffected by the letoff. 7

Thus the warp is maintained under substantially constant tension throughout the whole of each pick that is the tension in the Warp is not increased during the shedding and then decreased during the beating up and therefore the warp is not unduly stretched during shedding nor is it allowed to become unduly slack during the beating up so that the. beating up can be carried out satisfactorily for all densities of weave.

Again, there is no necessity for any variation in the weighting of the warp, so that a considerable amount of supervision can be dispensed with, and furthermore the fabric is woven quite evenly.

Another advantage lies in the fact that the letting back of the cloth and warp, is considerably simplified as this can be carried out simply by reversal of the take-up roller, the tension of the warp being maintained by angular displacement of the warp beamassembly in the anti-clockwise direction, there being no necessity for removal or adjustment of weights.

A further advantage of the invention consists in the fact that a relatively great depth of shedding can be obtained without the application of any undue strain to the warp, and furthermore an increased latitude in the position of the tappet for shedding is permissible.

By virtue of the fact that the shedding of the warp imposes no increase in tension upon the warp, the invention is particularly applicable to silk looms.

When the warp is taken from the warp beam in the manner indicated by the dotted line 45 the angle contained by the warp line from the warp beam to the back rest and from the-back restto the healds will vary as the diameter of the warp on the beam is reduced, so that there will be a very slight'variation in the warp tension asthe weaving proceeds but it is foundin-practice that this variation is negligible.

If desired, however, this slight variation in the warp tension can be compensated by gradual displacement of the pivot bearing 32 along the bracket 8 so as to vary the average rate of let off as the weaving proceeds, and thus slowly .to angularly displace the bracket 8 so as .to maintain approximately constant the angle contained between the respective aforesaid warp lines.

'In the case when the warp is taken from the warp boom in the manner indicated by the chain dotted line :46, this angulardisplacement of the bracket .8 can occur automatically .to maintain substantially constantthe angle contained. by the aforesaid warp lines particularly if the number of teeth on the ratchet wheel 20 is sufficiently great to ensure that a displacement of the spindle l1 takes place at every oscillation of the slay.

I declare that whatI claim is:

:1. A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets located one at each end of the warp beam and freely pivoted coaxially with the warp beam, a back carrier extending between and sup-ported'by saidbrackets and adapted to be rotated from a moving part of the loom, a toothed rim at each-end of the warp beam, a pair of toothed wheels mounted on the back carrier and engaging with the said toothed rims for rotating the warp beam, and loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp tension.

'2. A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxlally with the warp beam and extending upwardly from their pivotal axis, a back carrier extending between and supported by said brackets, a toothed wheel supported by saidbrackets and adapted to be driven from a moving part of the loom, a toothed rim on said warpbeam engaging with said toothed wheel, andloading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by'the warp.

3. A warp tensioning and let ofi mechanism for a'weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and'supported by-said brackets, a toothed wheel supported by said brackets and adapted to be driven from a moving part of the loom, a toothed rim on said warp beam engaging with said toothed wheel, a worm wheel arranged in angularly fixed relationship with said toothed wheel, a spindle supported by and extending longitudinally of one of said brackets, a Worm secured on said spindle and engaging said worm wheel, a ratchet wheel secured on said spindle, a lever freely pivoted on said spindie, a pawl pivoted to said lever, a spring on said lever to press the pawl against said ratchet wheel and an actuating member connected with said lever and intermittently displaced by a moving part of the loom to effect rotation of the warp beam, and loading means for applying a turning moment tosaid brackets to oppose the tuming moment applied thereto by the warp.

4. A warp tensioning and let off mechanism fora weaving loom comprising .a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with .the warp beam, a back carrier extending between and supported by said brackets, a toothed wheel supported by said brackets and adapted .to be driven from a moving part of the loom,.a toothed rim on said warp beam engaging with said toothed wheel, a warm wheel arranged in zangularly fixed relationship with said toothed wheel, .a spindle supported by and extending longitudinallyof one of said brackets, a worm secured on said spindle and engaging said worm wheel,.a ratchet wheel secured onsaid spindle, a lever freely pivoted on said spindle, a pawl pivoted to said lever, asp-ring on said lever to press .the pawl against said ratchet wheel, and an actuating member connected with said lever and intermittently displaced by a moving part of the loom to eifect rotation of the warp beam, the amplitude of movement of said actuating member at each displacement thereof being dependent upon the angular disposition of said bracketsand loading means for applying a turning moment to said brackets to oppose the'turning moment applied thereto by the warp.

5. Awarp tensioning and let ofi mechanism as claimed in claim 4 comprising a push. rod comprising a .push rod pivotally connected to said lever, an abutment on said push rod adapted for engagement by the slay of the loom :to cause periodic displacement of the push rod into a predetermined final position, resilient'means for urging the push rod in a direction towards the slay, a second abutment on said push rod a toothed wheel supported by said brackets, a

toothed rim on saidwarp beam engaging said toothed wheel, loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp;and actuating means for said toothed wheel including a push rod operatively associated therewith, an abutment on said push rod adapted for engagement by the slay of the loom to causeperiodic displacement of the push rod into a predetermined final position, resilient means for urging the push rod in a direction towards the slay, a second abutment on said push rod and an abutment member pivoted to one of said brackets and adaptedto engage said second abutment-in order to adjust the initial position of the push toothed rim on said warp beam engaging said toothed wheel, loading means for applying a turning moment to said bracketsto oppose the turning moment applied thereto by the warp, a worm wheel arranged in angularly fixed relationship with said toothed wheel, a spindle-sup- 7 ported by and extending longitudinally of one of said brackets, a worm secured on said spindle and engaging said worm wheel, a ratchet wheel secured on said spindle, a lever freely pivoted on said spindle, a pawl pivoted to said lever, a spring on said lever to press the pawl against said ratchet wheel, a push rod pivotally connected to said lever, an abutment on said push rod adapted for engagement by the slay oi the loom to cause periodic displacement of the push rod into a predetermined final position, resilient means for urging the push rod in a direction towards the slay, a second abutment on said push rod, and an abutment member pivoted to one of said brackets and adapted to engage said second abutment in order to adjust the initial position of the push rod in accordance with the angular disposition of the brackets.

8. A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and supported by said brackets, a toothed wheel supported by said brackets, a toothed rim on said warp beam engaging said. toothed wheel, loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp, and actuating means for said toothed wheel including a push rod operatively associated therewith, an abutment on said push rod adapted for engagement by the slay of the loom to cause periodic displacement of the push rod into a predetermined final position, resilient means for urging the push rod in a direction towards the slay, a second abutment on said push rod, and an abutment member pivoted to one of said brackets and adapted to engage said second abutment in order to adjust the initial position of the push rod in accordance with the angular disposition of the brackets, said abutment member being adjustable relatively to the bracket supporting it for adjustment of the initial position of the push rod.

9. A warp tensioning and let off mechanism for a Weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and supported by said brackets, a toothed wheel supported by said brackets, a toothed rim on said Warp beam engaging said toothed wheel, loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp and actuating means for said toothed wheel including a push rod operatively associated therewith, an abutment on said push rod adapted for engagement by the slay of the loom to cause periodic displacement of the push rod into a predetermined final position, resilient means for urging the push rod in a direction towards the slay, a second abutment on said push rod, and an abutment member pivoted to one of said brackets and adapted to engage said second abutment in order to adjust the initial position of the push rod in accordance with the angular disposition of the brackets, said abutment member being adjustable longitudinally of the bracket supporting it to vary its spacing from the pivotal axis of the bracket.

10. A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and supported by said brackets, a toothed wheel supported by said brackets, a toothed rim on said warp beam engaging said toothed wheel, loading means for'applying a turn"-' ing moment to said brackets to oppose the turning moment applied thereto by the warp and actuating means for said toothed wheel'including a'push rod operatively associated therewith, an 5 abutment on said push rod adapted for engagement by the slay of the loom to cause periodic displacement of the push rod into a predetermined final position, resilient means for urging the push rod in a direction towards the slay, a second abutment on said push rod, and an abutment member pivoted to one of said brackets and adapted to engage said second abutment in order to adjust the initial position of the push rod in accordance with the angular disposition of the brackets, and means for displacing the pivotal connection of said abutment member to the bracket supporting it'in a direction longitudinal ofsaid bracket to afford variation in the spacing of said pivotal connection from the pivotal axis of the bracket.

11. A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the Warp beam, bearings for said warp beam and brackets capable of adjustment to raise or lower the warp beam and said brackets, a back carrier extending between and supportedby said brackets, a toothed wheel supported by said brackets and adapted to be driven from a moving part of the loom, a toothed rim on said warp beam engaging with said toothed wheel, and loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp.

12. A warp tensioning and let off 'mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and supported by said brackets, 40 a toothedwheel supported by said brackets and adapted to be driven from a moving part of the loom, a toothed rim on said warp beam engaging with said toothed wheel, a quadrant extending from at least one of said brackets having a curved boundary concentric with the pivotal axis of the brackets, and aweight suspended from a point on the curved boundary of said quadrant.

13.- A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and supported by said brackets,

a toothed wheel supported by said brackets and adapted to be driven from a moving part of the loom, a toothed rim on said warp beam engaging with said toothed wheel, balance weights connected to at least one of said brackets, and loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp.

14. A warp tensioning and let off mechanism for a weaving loom comprising a freely pivoted warp beam, a pair of brackets freely pivoted coaxially with the warp beam, a back carrier extending between and supported by said brackets, a toothed wheel supported by said brackets, a toothed rim on said warp beam engaging said toothed wheel, loading means for applying a turning moment to said brackets to oppose the turning moment applied thereto by the warp, a worm wheel arranged in angularly fixed relationship with said toothed wheel, a spindle supported by and extending longitudinally of one of said brackets, a worm secured on said spindle and engaging said worm wheel, a ratchet wheel secured on said spindle, a lever freely pivoted on said spindle, a pawl pivoted to said lever, a spring on said lever to press the pawl against said ratchet wheel, a push rod pivotally connected to said lever, an abutment on said push rod adapted for engagement by the slay of the loom to cause periodic displacement of the push rod into a predetermined final position, resilient means for urging the push rod in a direction towards the slay, a second abutment on said push rod and an abutment member pivoted to one of said brackets and adapted to engage said second abutment in order to adjust the initial position of the push rod in accordance with the angular disposition of the brackets, and balance weights connected to said brackets for bringing the centre of gravity of the brackets and the elements which are angularly displaceable therewith substantially into coincidence with the pivotal axis of the brackets.

15. In a Weaving loom, the combination of a pivoted warp beam, a pair of pivoted side brackets having their pivotal axes coincident with the axis of said warp beam, said warp beam and said brackets being angularly displaceable under the influence of the warp tension acting in one direction, loading means for angularly displacing said warp beam and said brackets in the opposite direction, a back carrier supported by said brackets and extending therebetween, and a gear mechanism driven from a moving part of the loom and adapted to drive said warp beam, said brackets, back carrier, and gear mechanism being balanced whereby the center of gravity substantially coincides with the pivotal axes of said brackets and said warp beam.

HENRY LAKELAND. 

